Question

In the xy-plane, the line with equation

y = 4x - 28 crosses the x-axis at the point
with coordinates (a, b). What is the value
of a?
A. -28
B. -2
C. O
D. 5
E. 7​

Answer 1

Answer: E. 7

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Step-by-step explanation:

Any point on the x axis always has its y coordinate equal to 0.

Plug in y = 0 and solve for x

y = 4x-28

0 = 4x-28

4x-28 = 0

4x = 28

x = 28/4

x = 7

Therefore, the point (7, 0) is on the line y = 4x-28 and also on the x axis. This is known as an x intercept.

Comparing (7, 0) this to (a, b) shows that a = 7 and b = 0.